# Tagged Questions

For questions about geometric shapes, congruences, similarities, transformations, as well as the properties of classes of figures, points, lines, angles.

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### Given x coordinate difference find the angular difference

A point on a circle moved horizontally by $x$. How to find $\alpha$ in the picture below, knowing $x$, circle radius and center? I'm pretty sure this is doable but I just can't reach the solution. ...
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### Can you Prove or Disprove this?

In $a^n+b^n=c^n$ , $(a<b<c)$ , $a,b,n$ belongs to natural numbers, If $n>=b/2$ , $c$ lies between $(b,b+1)$. Also, only for $n=1,2$ , $c=b+1$.
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### Sierpinski triangle formula: How to take into account for 0th power?

The formula to count Sierpinski triangle is 3^k-1 .It is good if you don't take the event when k=0.But how can you write a more ...
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### Interesting circles hidden in Poncelet's porism configuration

This question is an investigation starting here, with a straightedge and compass construction of $ABC$ given $(R,r,h_A)$. The key lemma is the following one: Let $\Gamma$ be a circle with centre ...
### Show that the disc of radius $r$ centered at $A$ is the translation by $A$ of the disc of radius $r$ centered at the origin
This is a problem from the "Basic Mathematics" book by S.Lang (p. 225, exercise 12). My problem: Let $D(r, A)$ denote the disc of radius $r$ centered at $A$. Show that $D(r, A)$ is the translation ...